CLEP Biology Genetics & Biological Diversity — Questions and Answers
Question 1: What is the role of DNA in genetic inheritance?
- It provides energy for cell processes.
- It stores and transmits genetic information (Correct answer)
- It breaks down nutrients.
- It forms cell membranes.
Correct answer: It stores and transmits genetic information
Deoxyribonucleic acid (DNA) is the fundamental molecule of heredity. Its primary role is to store the genetic instructions necessary for an organism's development, functioning, growth, and reproduction, and to accurately transmit this information from one generation to the next.
Question 2: Which of the following best defines a gene?
- A type of cell.
- A structure in the cell nucleus.
- A sequence of DNA coding for a trait (Correct answer)
- A mutation in a chromosome.
Correct answer: A sequence of DNA coding for a trait
A gene is a specific segment of DNA that contains the instructions for building a particular protein or functional RNA molecule. These sequences are the fundamental units of heredity, determining an organism's traits and characteristics.
Question 3: How does meiosis contribute to genetic diversity?
- By producing identical cells.
- By increasing cell size.
- By reducing chromosome number and introducing variation (Correct answer)
- By eliminating mutations.
Correct answer: By reducing chromosome number and introducing variation
Meiosis is a specialized cell division process that produces gametes (sperm and egg cells) with half the number of chromosomes of the parent cell. During meiosis, processes like crossing over and independent assortment shuffle genetic material, creating unique combinations of alleles and significantly increasing genetic diversity in offspring.
Question 4: What is a phenotype?
- The genetic makeup of an organism.
- The mutation in DNA.
- The environment of the organism.
- The observable traits of an organism (Correct answer)
Correct answer: The observable traits of an organism
A phenotype refers to the observable physical or biochemical characteristics of an organism, such as eye color, height, or disease susceptibility. These traits are the result of the interaction between an organism's genetic makeup (genotype) and its environment.
Question 5: Which process results in the formation of gametes?
- Mitosis
- Fertilization
- Meiosis (Correct answer)
- Replication
Correct answer: Meiosis
Meiosis is the specific type of cell division that produces gametes (sex cells like sperm and eggs). This process reduces the chromosome number by half and introduces genetic variation, which is essential for sexual reproduction.
Question 6: What does homozygous mean in terms of alleles?
- Two different alleles
- A mutated allele
- Two identical alleles (Correct answer)
- No alleles present
Correct answer: Two identical alleles
In genetics, an organism is described as homozygous for a particular gene when it possesses two identical alleles for that gene. This means both copies of the gene, one inherited from each parent, are exactly the same.
Question 7: What is genetic drift?
- Natural selection of traits
- Random changes in allele frequencies (Correct answer)
- Artificial selection by humans
- Gene transfer through mating
Correct answer: Random changes in allele frequencies
Genetic drift is a mechanism of evolution characterized by random, chance fluctuations in the frequencies of alleles within a population, especially pronounced in small populations. Unlike natural selection, it does not involve differential fitness based on traits but is purely due to random events.
Question 8: What is the significance of a Punnett square?
- To study cell division.
- To determine the species of an organism.
- To predict genetic cross outcomes (Correct answer)
- To analyze evolutionary history.
Correct answer: To predict genetic cross outcomes
A Punnett square is a visual tool used in genetics to predict the probable outcomes of a genetic cross between two individuals. It systematically shows all possible combinations of alleles that offspring could inherit, allowing for the determination of expected genotypic and phenotypic ratios.
Question 9: Which term refers to an organism’s complete set of DNA?
- Phenotype
- Karyotype
- Genome (Correct answer)
- Genotype
Correct answer: Genome
The genome refers to an organism's complete set of DNA, including all of its genes and non-coding sequences. It contains all the hereditary information required to build, maintain, and reproduce that organism.
CLEP Biology Genetics & Biological Diversity
What is the role of DNA in genetic inheritance?